package com.duoduo.system.security;

import java.util.Collection;
import java.util.Iterator;

import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.authentication.InsufficientAuthenticationException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;

@Service
public class MyAccessDecisionManager implements AccessDecisionManager {

	// decide 方法是判定是否拥有权限的决策方法，
	// authentication 是释CustomUserService中循环添加到 GrantedAuthority 对象中的权限信息集合.
	// object 包含客户端发起的请求的requset信息，可转换为 HttpServletRequest request = ((FilterInvocation) object).getHttpRequest();
	// configAttributes 为MyInvocationSecurityMetadataSource的getAttributes(Object object)这个方法返回的结果，此方法是为了判定用户请求的url
	// 是否在权限表中，如果在权限表中，则返回给 decide 方法，用来判定用户是否有此权限。如果不在权限表中则放行。
	@Override
	public void decide(Authentication authentication, Object object, Collection<ConfigAttribute> configAttributes)
			throws AccessDeniedException, InsufficientAuthenticationException {

		if (CollectionUtils.isEmpty(configAttributes)) {
			return;
		}

		ConfigAttribute c;
		String needRole;
		for (Iterator<ConfigAttribute> iter = configAttributes.iterator(); iter.hasNext();) {
			c = iter.next();
			needRole = c.getAttribute();
			for (GrantedAuthority ga : authentication.getAuthorities()) {// authentication 为在注释1 中循环添加到 GrantedAuthority
																			// 对象中的权限信息集合
				if (needRole.trim().equals(ga.getAuthority())) {
					return;
				}
			}
		}
		throw new AccessDeniedException("no right");
	}

	@Override
	public boolean supports(ConfigAttribute attribute) {
		return true;
	}

	@Override
	public boolean supports(Class<?> clazz) {
		return true;
	}
}
